Here's a breakdown of costs for Mueller's Russia investigation so far

The US Justice Department says around $17 million was spent so far in the ongoing Russia investigation being conducted by special counsel Robert Mueller.

According to an earlier spending report, the DOJ said $6.7 million was spent in the first 4 1/2 months of the investigation, which began in May 2017. Another $10 million was spent within a six-month period between October 2017 and March 2018, according to the DOJ expenditure report.

Trump has frequently railed against the investigation, calling it a "witch hunt" and scrutinizing its cost.

Funding for the investigation comes from the Treasury Department and it is not tied to the annual budget, Politico reported on Thursday.

The federal Russia investigation being conducted by special counsel Robert Mueller has so far cost about $17 million, according to the DOJ and a Politico report on Thursday.

The special counsel's office released its mandatory statement of expenditures itemizing costs accrued between October 2017 and March 2018. About $10 million was spent within that six-month timeframe. About $6.7 million was spent in the opening 4 1/2 months of the probe, which began in May 2017.

Here's a breakdown of the costs for October 2017 through March 2018, which according to the special counsel's office, is within the approved budget:

Salaries and benefits for employees in the special counsel's office: $874,069

Cost of Justice Department employees temporarily assigned to the special counsel's office: $1.9 million

Travel expenses: $532,340

Information technology services: $226,730

Supplies and materials: $29,694

The Russia investigation was launched as part of an effort to determine the extent of Russian interference in the 2016 US presidential election, and to see whether members of Donald Trump's campaign colluded with Russia.

Mueller has also been working to determine whether Trump attempted to obstruct justice in connection with the investigation after he took office.